A disk drive assembly is a computer, mass-storage device from which data may be read and/or to which such data may be written. Typically, a disk drive assembly includes one or more randomly-accessible rotatable storage media, or disks, upon which the data is encoded by various means. In a magnetic disk drive, the data is encoded thereon as bits of information comprising magnetic field reversals grouped in tracks on the magnetically-hard surface of the rotating disk or disks. When the disk drive assembly includes a plurality of disks, the disks are typically stacked in a generally parallel and spaced-relationship and affixed at their inner diameters to a common hub.
A spindle motor imparts rotational forces to rotate the rotatable storage media at a rotational speed. A magneto resistive (MR), or other, head transducer is positionable proximate to the rotating storage media to read the data from the magnetic media forming the storage media. The MR head transducer detects magnetic field signal changes from magnetic media. Such detection is made due to changes in the resistance of the MR head transducer responsive to changes in the direction and amount of magnetic flux being sensed by the transducer.
The MR head transducer is supported by an actuator arm. Movement is imparted to the actuator arm, and, hence, to the MR head transducer by appropriate actuation of a voice coil motor (VCM) of an actuator assembly. Successive read and write operations can be selectively performed by suitably positioning and repositioning the MR head transducer and associated inductive write transducer proximate to selected locations of the storage media.
Advancements in technology have permitted the development and implementation of successive generations of disk drive assemblies of ever-improving performance characteristics and memory capacities, of ever-smaller physical sizes, and at ever-lesser costs.
Several problems inherent of a disk drive assembly become increasingly problematical, however, when attempts are made to provide a disk drive assembly of such improved performance, increased memory capacity, smaller size, and lower cost.
For instance, when the disk drive assembly is to be operated at increased read and write rates, the disk drive assembly becomes more susceptible to misoperation due to the occurrence of an offtrack condition. An offtrack condition occurs when the actuator arm and the MR head transducer overshoot the intended location of the rotating storage media at which a read or write operation is to be performed responsive to actuation of the VCM. An offtrack condition might also occur if an external shock force is applied to the disk drive. Such conditions are sometimes referred to as "bumps". Increased velocities, for instance, at which the VCM moves the actuator arm increases the incidences of offtrack conditions. Also, the quality of the mounting by which the disk drive assembly is mounted in position also affects the incidence of offtrack conditions. A mounting of lesser quality, such as that might be precipitated through the use of an inexpensive mounting, might precipitate an increased incidence of bumps.
Manufacturability problems associated with the manufacture of disk drive assemblies also affects disk drive performance. For instance, tolerances associated with the manufacture of MR head transducers introduces variability in disk drive assembly performance. MR head transducers are also susceptible to electro-migration which adversely affects the longevity of the transducers. In the design and construction of a disk drive assembly, consideration must, therefore, be given to such manufacturability problems and problems associated with electro-migration.
Manufacturability problems are also associated with airlocks which form portions of disk drive assemblies. An airlock is a safety interlock. The airlock is operable to ensure that the rotatable storage media is rotating prior to movement of the MR head transducer thereupon. Tolerances associated with the manufacturer of airlocks introduces variability in disk drive performance as different airlocks open at different rotational speeds of the storage media. And, a single airlock may be operable to open at different rotational speeds responsive to changes in the ambient conditions, such as, e.g., the altitude at which the disk drive assembly is positioned.
Thermal asperities and stiction are also problems which can adversely affect performance of a disk drive assembly. Consideration must also be given to such problems when constructing a disk drive assembly.
Therefore, when designing and manufacturing disk drive assemblies with the goal of providing a disk drive assembly of improved performance and increased memory capacity, consideration must be given to the aforementioned problems.
What is needed is a disk drive assembly of improved performance, increased memory capacity, and reduced cost which reduces the aforementioned problems associated with disk drive assemblies.
It is in light of this background information related to disk drive assemblies that the significant improvements of the present invention have evolved.